mutation_original.rb

class AddTeacherToSite < Mutation
  def required_arguments
    [
      model_or_id(:site, Site),
      model_or_id(:teacher, Teacher),
    ]
  end
  
  def policy
    # list the privacy policy required for this
  end
  
  def commit
    # use passed in args to perform the update
  end
end 
# this call checks privacy policy, validates the args, and then calls commit
AddTeacherToSite.execute!(viewer, site: …, teacher: …)